by Jochen Szangolies

The humble bumblebee is a mainstay character of a certain kind of motivational tale. One widely shared version of the story goes as follows:

The mathematical relationship between the wings and the weight of the bumblebee shows that flight is impossible for it. But the bumblebee does not know this, so it flies.

It’s a good line. It has a clear, uplifting message: no matter what other people—even supposed authorities—say, you can achieve your goals. What matters is what you believe (for if the bumblebee had believed the scientific verdict, it would surely have remained safely aground). It’s also a cautionary tale against scientific hubris: all its ambitions to unravel the mysteries of the cosmos thwarted by a tiny garden insect.

But—and I’m sorry to have to be the party pooper here—the problem is that it’s just not true. There is no great mystery about the bumblebee’s flight. But the nature of the error being made here is instructive (and more interesting than the myth).

In 1934, French entomologist Antoine Magnan, together with his assistant André Sainte-Lague, performed a short calculation for his book, Le Vol des Insectes (“The Flight of Insects”), which concluded that the lift produced by the bumblebee’s comparatively small wings could not suffice to keep its stocky body airborne—it would have to be about ten times lighter to work.

So what went wrong? Did they just bungle the calculation? No—their math checks out. The problem lies in assuming a particular model of flight, suitable for airplanes, but ill fitted to the case at hand. Read more »